What is dark matter, and why is it essential to understanding the universe? This book explores the concept of dark matter, a mysterious substance that does not emit light or energy yet exerts a gravitational pull on visible matter in the universe. It discusses the evidence for dark matter’s existence, such as the rotation curves of galaxies and gravitational lensing, and the leading theories regarding its composition. The narrative delves into the ongoing search for dark matter particles, the experiments designed to detect them, and the implications of dark matter for cosmology and particle physics. By exploring the unknowns of dark matter, the book sheds light on one of the most compelling mysteries of modern astrophysics.